ELECTRIC ARC SURFACING AND WELDING METHOD WITH COMBINATION TYPE GAS SHIELD Russian patent published in 2008 - IPC B23K9/04 B23K9/173 B23K103/04 

FIELD: processes for surfacing and welding steel articles in gas shield atmosphere.

SUBSTANCE: method comprises steps of preliminarily blowing welding zone through outer cylindrical nozzle by means of shield gas such as argon; applying electric current from separate power source to inner cylindrical nozzle being in the form of hollow non-melting electrode and igniting arc; after forming high-temperature region in electric arc and its shifting to cavity of non-melting electrode, supplying to said region additive wire connected with pulse power source and shield gas containing mixture of argon and nitrogen; selecting volume relation of argon and nitrogen in said mixture in range (10 - 20) : 1; determining flow rate of mixture according to relation Q = kd where k -experimentally determined factor taking into account influence of additive wire diameter upon flow rate of gas mixture; d - diameter of additive wire; selecting relation of electric current taken from hollow non-melting electrode and pulse electric current applied to additive wire in range 2 - 2.5. According to invention shield gas contains nitrogen whose content is increased till 0.15 mass%.

EFFECT: improved quality of seam metal due to increased nitrogen content in shield gas.

3 dwg, 1 tbl, 1 ex